DESCRIPTION
    Base class for handling the import of the spreadsheet file

    Subclass this.

SYNOPSIS
    # Your Importer class package My::Importer;

    use Moose;

    extends 'Data::Importer';

    sub mandatory_columns { return [qw/name description price/]; }

    sub validate_row { my ($self, $row, $lineno) = @_; # XXX validation #
    return $self->add_error("Some error at $lineno") if some condition; #
    return $self->add_warning("Some warning at $lineno") if some condition;
    $self->add_row($row); }

    sub import_row { my ($self, $row) = @_;
    $schema->resultset('Table')->create($row) or die; }

    # Import the file like this

    my $import = My::Importer->new( schema => $schema, file_name =>
    $file_name, ); $import->do_work;

ATTTRIBUTES
  schema
    Yes, we use DBIx::Class. Send your schema.

  dry_run
    Set to true if this is only a test

  file_name
    The name of the spreadsheet

  import_type
    Three formats are supported, csv, xls, ods

  mandatory
    Required input columns

  optional
    Required input columns

"PRIVATE" ATTRIBUTES
  import_iterator
    An iterator for reading the import file

  rows
    An arrayref w/ the rows to be inserted / updated

  warnings
    An arrayref w/ all the warnings picked up during processing

    These methods are associated with warnings:

   all_warnings
    Returns all elements

   add_warning
    Add a warning

   join_warnings
    Join all warnings

   count_warnings
    Returns the number of warnings

   has_warnings
    Returns true if there are warnings

   has_no_warnings
    Returns true if there isn't any warning

   clear_warnings
    Clear out all warnings

  errors
    An arrayref w/ all the errors picked up during processing

    These methods are associated with errors:

   all_errors
    Returns all elements

   add_error
    Add a error

   join_errors
    Join all errors

   count_errors
    Returns the number of errors

   has_errors
    Returns true if there are errors

   has_no_errors
    Returns true if there isn't any error

   clear_errors
    Clear out all errors

  timestamp
    Time of the import run.

METHODS
  mandatory_columns
    Builds the mandatory attribute, which gives an arrayref with the
    required columns.

  optional_columns
    Builds the optional attribute, which gives an arrayref with the optional
    columns.

  do_work
    Import a file

  validate
    Validates the import file

  validate_row
    Handle each individual row.

    This has to be written in the subclass

  import_run
    Imports the nodes after validate has been run

  import_transaction
    Called inside the transaction block.

    This is the method to add method modifiers to if processing before or
    after the row import loop is necessary.

  import_row
    Handle each individual row.

    This has to be written in the subclass

  import_failed
    Called if the import failed for some reason

  import_succeeded
    Called after the import has finished succesfully

  report
    Make a report of what happened

